1. Field of the Invention
The present invention relates to an apparatus for sensing a type of an unbalance of a washing machine and a method thereof, and more particularly, to an apparatus for sensing a type of an unbalance of a washing machine with using a multi-axis acceleration sensor, and a method thereof.
2. Description of the Background Art
Generally, a washing machine serves to wash laundry by applying a mechanical force such as friction, vibration, etc. to the laundry immersed in washing water.
The washing machine performs a washing operation for washing laundry mixed with washing water by applying a mechanical force, a rinsing operation for separating the washing water from the laundry, and a dehydrating operation for separating the rinsing water from the laundry.
However, when the laundry is not uniformly distributed (unbalance occurrence) in the washing machine, vibration and noise are caused in the dehydrating operation. Therefore, a function for sensing a type of an unbalance of the washing machine and uniformly distributing the laundry is required.
FIG. 1 is a flowchart showing a method for sensing a type of an unbalance of a washing machine and dehydrating laundry in accordance with the related art. As shown, the related art method for sensing a type of an unbalance of a washing machine and dehydrating laundry comprises: driving a washing motor with a low speed (S11); detecting an unbalance amount of laundry by detecting a variation amount of an rpm of the motor (S12); comparing the detected unbalance amount with a preset reference value (S13); and uniformly distributing the laundry when the detected unbalance amount is greater than the preset reference value (S14a), and increasing the rpm of the washing machine when the detected unbalance amount is less than the preset reference value (S14b).
In the step of detecting an unbalance amount (S12), the rpm is periodically detected with using a speed detecting sensor mounted at a washing machine motor, and an unbalance amount is detected based on a difference between a maximum value and a minimum value of the rpm.
Whether a dehydrating process is to be immediately performed or is to be performed after the laundry uniformly-distributing process is judged by comparing the detected unbalance amount with the preset reference value.
However, in the related art washing machine, since an unbalance amount is detected by detecting only an rpm of a motor, an unbalance having a less correlation with the rpm can not be detected.
For instance, when an unbalance due to a diagonal load is caused, vibration of a tub is severely generated in upper and lower directions. However, the rpm of the motor is not greatly decreased, and thus the unbalance is not detected. When a dehydrating process is performed without considering the unbalance, noise is greatly caused and a mal-function of the washing machine is caused.